Objectification of pain assessment in children and adults

The pain is generally considered to be a subjective feeling because there is no standard for the measurement device. Commonly used pain rating scales have their limitations due in part to the patient’s age, the severity of the underlying disease or a reference to the real-time of pain and its severity. The aim of the ideal pain assessment tool should be measured pain intensity in real time, accurate assessment of pain, speed of reaction and scale appropriate to its value or regardless of age group. Device that meets these conditions is the method of skin conductivity tests. This method uses the phenomenon of skin conductivity as a measure to stimulate the sympathetic nervous system due to pain stimulus. Activation of the sympathetic fibers innervating sweat glands induces release of the contents of these glands (called emotional sweating) while reducing drag and increasing skin conductivity. Quick absorption of sweat released again reduces the conductivity. The resulting differential conductivity is read as a single pendulum which has its strength (wave amplitude) and slope (the time gap between the top of the cavity). The stimulation of the sympathetic system is determined by the amplitude (intensity) and frequency (number fluctuations or oscillations of conduction at the time) and presented as their resultant in the form of an index. Painful stimuli induce a rapid increase in emotional sweating and skin conductivity fluctuations. When a painful stimulus ceases, skin conductance decreases immediately. These changes are recorded by electrodes placed on the well-equipped with sweat glands, skin, the palms of r hand or sole of the foot. The resulting conductivity fluctuations reach the evaluation unit, where the transformation is analyzed using appropriate software. Another device that serves the objective assessment of pain is Analgesia-Nociception Index (ANI). It is based on heart rate variability (HRV Heart Rate Variation), and differentiating components of the heart rate cycle between inspiration and expiration (Fourier analysis of harmonic and non-harmonic components of the ECG). The analysis is the degree of tension n X (parasympathetic response). If the patient does not feel pain, parasympathetic dominant rhythm (HR increases during inspiration and falls during expiration), which corresponds to a high-value of ANI. In the case of severe pain feel for the patient, the response of the parasympathetic system is disturbed during exhalation, and the ANI decreases. ANI Monitor allows to track changes in real time on a graph and numeric values. Data are presented on the screen in the form of graphs of ANI instantaneous and ANI average for the last four minutes. ANI index size is inversely proportional to the severity of pain stimulation, and therefore, neither is sometimes called „comfort index”. No less than 50 indicates insufficient analgesia or in the range of 50 to 70 refers to the correct analgesia, while ANI above 70 indicates of hiperanalgesia risk.